Filtering element.



K. KIEPER. FILTERING ELEMENT.

APPLICATION FILED JUNEH. 1906.

FIG. 1

FIG. 2

F 'N W tnesses. Inventor. 5 m M @m Ja PATENTBD OCT. so, 1906.

KARL KIEFER, OF CINCINNATI, OHIO.

FILTERING ELEMENT.

Specification of Letters Patent.

Patented Oct. 30, 1906.

Application filed June 3. 1905. Serial No. 263.671.

To all whom zLt may concern.-

Be it known that I, KARL KIEFER, a citizen of the United States, and aresident of Cincinnati, in the county of Hamilton and State of Ohio,have invented a new and useful Improvement 'in Filtering Elements, ofwhich the following is a specification.

My invention relates to filter elements of freshly-compressed pulp forthe filtration of beer, wines, &c. Wherever the words compressed pulpare used in this specification, they are to be understood to meancompressed moist pulp in this art and not manufactures of paper.

The purpose of this invention is to still more perfect and simplify theconstruction. as patented by me January 10, 1905, No. 779,607.

In the drawings, Figure 1 shows an outlet liquid-conductor incross-section. Fig. 2 shows several superim osed filter elements incross-section, of whic the top one is in the act of being lowered uponthe ones underneath.

My new filter elements are very simple and consist of filter mass M,compressed in a special filter-pulp-packing machine, such as the onepatented to me January 10, No. 779,548. Embedded in this filter mass isa liquid-conductor for the clear liquid consisting only offiber-retaining screen. For the definition of fiber-retaining screen Irefer to my Patent No. 779,607. As shown in the drawings, there are twofiber-retaining screens of different size, the large one S and thesmaller one S. In smaller machines one screenwill do; but in larger onesit is preferable to add a second screen S of less diameter. I have foundthat this fiber-retaining screen presents an outlet area sufficientlylarge for the clear liquid, although the filter mass M ma be compressedin a semifiuid state from bot sides against this screen. It ispreferable to use twilled screen, as a very strong pliable screen can beroduced thereby. Such screen is common y used in the art for pulpfiltersand is itself not new.

The center part of the filter mass is, as indicated by the increasednumber of dots, com pressed to such an extent that the filter-pul ceasesto be porous. There is just as much filter mass contained within thecenter part of the filter mass M as is at any other part; but it isconsiderably more compressed from three to four times. This com ressionmy patent application, Serial No. 258,374, filed May 1, 1905, forFiltering elements and method of making same; but it can be donesuccessfully by producing a homogeneous filtering layer first and comressing it afterward. I will state that whi e pulp-filter layers havebeen compressed to some extent formerly in the art in a lateral way thiscompression heretofore has not been efiicient enough to prevent thecloudy liquid from entering the clear-liquid conduits, for the reasonthat the compression was based on the wrong principle. Paperulp whencompressed to a certain density oses its plasticity in certaindirections. t cannot be compressed like plastic clay, so it expands toall sides; but it can only be compressed in one direction. I may use theexpression which designates it best that while it may be flattened upona surface it cannot be spread thereon. All devices therefore which relyon s reading alone or in combination with flattening are failures.

N, the inlet liquid-conductor, consists of a single coarse wire screen,as described in Patent No. 779,607, patented to me January 10, 1905.This has a strong flange F on its center to take up the space caused bythe compression of the center part of the filter mass and combines thecenter of all filter elements to a solid tube, interrupted only by theoutlet between the fiber-retaining screen. As is easily visible from thedrawin s, the cloudy liquid cannot pass to the cleariquid conduit in thecenter unless it passes between the center flanges F and thestrongly-compressed filter mass or through the filter layer. These partsvirtually act like a gasket, and so successfully separate the cloudyliquid from the clear-liquid conduit. The clear liquid issues betweenthe capillary spaces formed by the fiber-retaining screens S into thecenter hole. The flange F is fastened in the center to thecoarse-wrre-screen conductor. The flange F is preferably made of twoparts and screwed upon the coarse wire screen, and the interstices ofthe screen are filled out with tin where they are inclosed by theflange, which. gives the coarse screen additional strength and rigidityand also prevents impurities from settling within the flanges.

All filter elements are commonly used in connection with so-calleddrums, which are hollow and water-tight casings. The former are slightlysmaller than the casing, so as to produce a small annular s ace betweencan be done in one operation, as s own in 1 them and the drum, and theiet liquid-condoctors are adapted to center the filter elements inreference to each other and to the drum by having a loose fit within thelatter. In the drawings such drum is indicated in cross-section by U.

The filter elements must be supported rigidly to some part of thefilter, so that the ac tion of the liquid to be filtered upon the filtermass will not cause the collapse of the whole series of filter elements.In filter elements with a central liquid-outlet this can be successfullydone by supporting each layer by the hub as, for instance, shown in myIteissue Patent No. 12,347, May 16, 1905, Where a series offilterelements Within a drum or casing is supported by metal hubs forming arigid con11nunication-column within the fil ter. In this construction,however, it is required that all the hubs must be of a certain height inorder to fill up all the space within the drum. It is, however,sometimes difiicult to make all the filter layers equal in thickness,and the strict requirement that each filter layer should be of a certainheight causes a different compression relatively according to the amountof mass that has been used. In the present construction this is overcomeby using the central compressed parts of the filter layers for thesupport of the filter elements. I have found that when moist filter-pulpis compressed considerable of the elasticity of the fiber which itexhibits in its dry state is regained accordin to the amount of waterexpressed. The e asticity of the pulp, therefore, is inverselyproportionate to its porosity, and when using a number of filter layerswithin a drum or casing, such as is used in the art, the elasticity ofthe central compressed parts in the present construction will allow ofsufiicient variation within the casing and at the same time pro duce asufficiently rigid su port for all the filter lavers in reference to tie base.

If, for instance, twenty elements are packed on top of eachother anditis seen that the filterdrum is not quite full, an additional filterelement may be placed on top of the pile and by a little strongercompression squeezed into the filter-drum, although without thisadditional compression it would have appeared that there was not enoughspace for this additional element. This advantage is derived from thefact that moist paper-pulp at a certian stage of compression becomeselastic, the natural elasticity of the fiber asserting itself when acertain amount of water has been expressed.

Another advantage is that even if the packing-machine should not packthe filter elements to an equal tightness the pressure will equalizeitself afterward within the filter.

The fourth advantage is that this pressure upon all the filter elementscan be regulated by packing more or less filter elements on top of eachother into an equal space.

A lifting instrument, for which I have ap plied especially in myapplication, Serial N 0. 252,268, filed March 27, 1905, can be utilizedfor placing said filter elements. The center hole in the filter mass Mshould preferably be made a little larger than the hole in the centerhub F of the inlet liquid-conductor, as shown in the drawings. This willfacilitate the lifting out of the elements by means of the liftin rinstrument.

What claim as my invention, and desire to secure by Letters Patent, is

1. In a filter, the combination with a drum or casing, of circularfiltering layers of compressed fibrous pulp of a diameter somewhatsmaller than the casing, of liquid-conductors draining or supplyin suchfiltering layers, said filter layers and fiiquid-conductors supported inreference to the base by an elastic superposed column composed ofnon-compressible parts of the liquid-conductor, in alternation withcompressed parts of the filter layer, the latter parts compressed toelastic stage.

2. In a filter, the combination with a drum or casing, of circularfiltering layers of com pressed 'brous pulp of a diameter somewhatsmaller than the casing, of liquid-conductors draining or supplying suchfiltering layers, said filter layers and liquid-conductors sup ported inreference to the base by an elastic superposed column composed ofnon-com pressible parts of the liquid-conductors in alternation withcompressed parts of the filter layers.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

KARL KIEFER.

Witnesses:

G. W. WERDEN, LEO MARcUsoN.

